The subject invention relates to water-repellent compositions. More particularly, the invention relates to water-repellent compositions and methods whereby wood is treated with the compositions so as to obtain water-repellency and optionally wood preservacy and/or conductivity.
There has long been a need for water-repellent compositions. Such compositions find use on a variety of substrates. One area in particular where water-repellents have found use has been in the treatment of wood. This is especially true for wood which is exposed to the outside environment and which conventionally is not provided with the protection offered by paint. For example, certain portions of wood windows do not get painted. Such portions when continually contacted with water and subjected to changing weather conditions will swell, crack, and eventually rot. Generally, wood which is intended for exposure to the outdoors is treated prior to installation. Thus, wood which is to be used in a window frame is conventionally given a treatment with a water-repellent- and wood preservative-containing composition. After this treatment, the wood substrate is coated or strained for appearance purposes and an added measure of protection.
In some methods of wood treating, the treated and dried wood is further treated with a conductive solution and thereafter given a topcoat with electrostatic spray equipment. The advantage of the electrostatic spray operation is that the wood substrate is more evenly and completely topcoated. An obvious saving of time and expense would be if the wood could be given one treatment with a composition containing a water-repellent, wood preservative and conductor. The application of such a composition followed by an electrostatic spray step has definite time-saving and expense advantages. However, it has been found that the compounds effective as conductors when used with conventional wood treating water-repellents tend to adversely affect the water-repellency of the treated wood. This is true whether the conductors and water-repellents are mixed together prior to application to the wood or are applied separately.
There is a need in the wood coating art for compositions which are capable of providing a wood substrate with good water-repellency, especially at low cost. A special need is for compositions which are capable of providing a wood substrate with water-repellency and, at the same time, impart a conductive charge to the substrate such that a topcoat can thereafter be electrostatically spray applied. There has now been found compositions which are capable of providing the above advantages.
As used herein, all percents and ratios are by weight unless otherwise indicated.